Topic: How would I model this?!?

[Matt__W]

How would I go about modeling this octagonal canopy?

Any suggestions?  I haven't used the stock 3D tools (other than solid, union and subtract) so I'm not sure what's available.

[jnieman]

Obviously you only have to model one of the 8 triangles (if you're looking in plan view) at a time, and just array it to make the octagon.

I'd start with...

Draw a 3d poly that forms the 'entrance arch' I guess I'd call it... from the foot to the peak of arch, to the next foot.  Then drawn another arch at the next section...

ah screw it this is getting weird to explain and me no goot words much...

give me a minute and I'll upload an example

hint = loft 2d sections

[jnieman]

I copied it over as I did each step... and the profiles may be a bit different than in the picture, but the cool thing about loft is that you can alter the cross sections used for the lofted object, after it's lofted...

If desired, you can turn it into a solid using THICKEN command and entering a thickness.

However, I tried .25 and .01 and it failed... the cross section where it comes to a point is probably too small to allow it, so if you widen that line, you should be able to thicken it... I'll let you know if it let me.

[jnieman]

Yea, nevermind, I tried a few things and cannot get THICKEN to work.

I increased the end segment width (at peak) to 1/4" and tried thickening it at random values from .0001" to 12" and always gave me "Cannot thicken object with specified value"

May have to stick with surfaces, rather than solids.

Also, if you extrude a cylinder along the two "rails" where the tent poles go, it'll hide make it seem a little more realistic.

[deegeecees]

I'd use a mesh.

[jnieman]

This may get you started on that lamp post too...

Some reason, I couldn't get shell to work on the glass, so I copied the glass in place, scaled one by 0.95 then subtracted the smaller from the large... it's dirty and inaccurate, but it works for show and tell models.

[Matt__W]

For that canopy, how did you draw the arcs at an angle like that?

[deegeecees]

Thanks for the lesson Josh. Never used LOFT before, and with your examples in the pitched tent dwg, I see how you achieved what you did. I just lernt sumthin.

[mjfarrell]

For that canopy, how did you draw the arcs at an angle like that?

start in the nearest plane, draw an arc, then use 3drotate on it and chose a plane to rotate it in.

[Spike Wilbury]

I copied it over as I did each step... and the profiles may be a bit different than in the picture, but the cool thing about loft is that you can alter the cross sections used for the lofted object, after it's lofted...

If desired, you can turn it into a solid using THICKEN command and entering a thickness.

However, I tried .25 and .01 and it failed... the cross section where it comes to a point is probably too small to allow it, so if you widen that line, you should be able to thicken it... I'll let you know if it let me.

Good one! Josh.

I am a neophyte in 3D if you ask me....

[Matt__W]

For that canopy, how did you draw the arcs at an angle like that?

start in the nearest plane, draw an arc, then use 3drotate on it and chose a plane to rotate it in.

That's all?  I thought/was hoping maybe there was some kind of fancy 3D modeling tool I could use.  I've never liked the 3D rotate command.

[jnieman]

actually I'm still stuck in my old-ass habits of changing the UCS... and using the regular rotate.

(normal)Rotate always rotates in the XY plane... so the AXIS of rotation is always parallel to the Z axis...

So for example, I modified the UCS so that the Z axis went through both "feet" of the first arc, then rotated it an arbitrary angle that looked right.

I used 3DRotate a few times but then would forget, lapse into my old habits, and I guess I never got used to it enough to use it regularly.

So whatever makes more sense to you, I guess.

No thanks needed... I'm glad to be of service whenever I can!  I get so much from y'all, it's nice to be on the other side of things for once

[mjfarrell]

For that canopy, how did you draw the arcs at an angle like that?

start in the nearest plane, draw an arc, then use 3drotate on it and chose a plane to rotate it in.

That's all?  I thought/was hoping maybe there was some kind of fancy 3D modeling tool I could use.  I've never liked the 3D rotate command.

Try it now with all the helper glyphs ported from other apps, it's actually pretty likable these days.
More fun in an ISO view....

[jnieman]

For that canopy, how did you draw the arcs at an angle like that?

start in the nearest plane, draw an arc, then use 3drotate on it and chose a plane to rotate it in.

That's all?  I thought/was hoping maybe there was some kind of fancy 3D modeling tool I could use.  I've never liked the 3D rotate command.

Try it now with all the helper glyphs ported from other apps, it's actually pretty likable these days.
More fun in an ISO view....

Now if only the MATERIALMAP would use a base-point / end-point for the angle of rotation as well... the MATERIALMAP just makes you eye-ball it... and it's a poor-enough function that you can't get any precision out of it.  So if you need to rotate your brick pattern 90degrees, I always seem to end up just a BIT off over a long enough distance.... *thinks he should have started this with 'you know what really GRINDS my GEARS?*

[mjfarrell]

Uh, how do you normally do your material UVW mapping there J-dawwg? 
I do not recall having said challenge.

[jnieman]

Uh, how do you normally do your material UVW mapping there J-dawwg? 
I do not recall having said challenge.

I never messed with material mapping until 2007 and later.  Before that I did machine/fab drafting and the 3d was sufficient with a non-image texture.. just needed to be shiny or painted...

But now, MATERIALMAP uses that 3-axis spinny thing, but it doesn't SEEM to allow me to just rotate about x, 90 degrees... for instance.  Am I missing something?

[mjfarrell]

You could start at the Material level itself.

Then you can also use the other object mapping defaults, planer,box,cylinder, etc.

command: _MaterialMap
Select an option [Box/Planar/Spherical/Cylindrical/copY mapping to/Reset
And that all of them can be rotated with the Gizmo
mapping]<Box>: _S

And then get to the  GIZMO

Notice that while using the Gizmo I can Snap an angle using end points?  You have more control that you think.

[jnieman]

You could start at the Material level itself.

Then you can also use the other object mapping defaults, planer,box,cylinder, etc.

command: _MaterialMap
Select an option [Box/Planar/Spherical/Cylindrical/copY mapping to/Reset
And that all of them can be rotated with the Gizmo
mapping]<Box>: _S

And then get to the  GIZMO

Notice that while using the Gizmo I can Snap an angle using end points?  You have more control that you think.

The problem with rotating within the material, is that I may need it one way for one piece, and another for a second piece... which then would lead to having more than one material per rotation... which sucks, imo.  So I didn't go that route.

I'll try messing around a bit more using your drawings, but don't have time atm.  tbh, I always felt this was one thing I just didn't know the "proper" way yet, but hadn't gotten around to looking into.  It's hard to find good detailed resources for rendering/material-mapping in Autocad... probably because most people who rely on it have better programs for it